Skip to main content
SpringerLink
Log in

Extreme ultraviolet flashes of solar flares observed via sudden frequency deviations: Experimental results

  • Published:
Solar Physics Aims and scope Submit manuscript

Abstract

Properties of solar-flare EUV flashes measured via a type of ionospheric event, called a sudden frequency deviation (SFD), are presented. SFD's are sensitive to bursts of radiation in the 1–1030 Å wavelength range. He ii 303.8 Å, O v 629.7 Å, HL γ 972.5 Å and C iii 977.0 Å have essentially the same impulsive time dependence as the 1–1030 Å flash responsible for SFD's. Soft X-rays (2–20 Å) and certain EUV lines have a much slower time dependence than the 1–1030 Å flash. Most SFD's have some fine structure, but marked quasi-periodicity in EUV flashes is quite rare. EUV flashes are closely associated with hard X-ray bursts, white-light emission, microwave radio bursts and small bright impulsive kernels in the Hα flare. The intensity of EUV flashes depends on the central meridian distance of the Hα flare location; the intensity decreases at the limb. The total energy radiated in the 10–1030 Å flash for the largest events observed is about 1031 ergs.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Agy, V., Baker, D. M., and Jones, R. M.: 1965, NBS Tech. Note No. 306 (U.S. Government Printing Office, Washington, D.C.).

    Google Scholar 

  • Arnoldy, R. L., Kane, S. R., and Winckler, J. R.: 1968, Astrophys. J. 151, 711.

    Google Scholar 

  • Basu, S. and Chowdhurry, S. R.: 1969, J. Geophys. Res. 74, 4175.

    Google Scholar 

  • Chan, K. L. and Villard, O. G. Jr.: 1963, J. Geophys. Res. 68, 3197.

    Google Scholar 

  • Davies, K. and Donnelly, R. F.: 1966, J. Geophys. Res. 71, 2843.

    Google Scholar 

  • De Jager, C.: 1964, Research in Geophysics 1, MIT Press, 1–42.

  • Donnelly, R. F.: 1968, Solar Phys. 5, 123.

    Google Scholar 

  • Donnelly, R. F.: 1969, Astrophys. J. 158, L165.

    Google Scholar 

  • Donnelly, R. F.: 1970, ESSA Tech. Rept. ERL 169-SDL 14 (U.S. Government Printing Office, Washington, D.C.).

    Google Scholar 

  • Friedman, H.: 1969, Solar Flares and Space Research (ed. by C. De Jager and Z. Švestka), North-Holland Publ. Co., Amsterdam, p. 87.

    Google Scholar 

  • Garriott, O. K., DaRosa, A. V., Davis, M. J., and Villard, O. G. Jr.: 1967, J. Geophys. Res. 72, 6099.

    Google Scholar 

  • Garriott, O. K., DaRosa, A. V., Davis, M. J., Wagner, L. S., and Thome, G. D.: 1969, Solar Phys. 8, 226–39.

    Google Scholar 

  • Grebenkemper, C. J.: 1969, of the U.S. Naval Res. Lab., Washington, D.C., private communication.

  • Hall, L. A. and Hinteregger, H. E.: 1969, Solar Flares and Space Research (ed. by C. De Jager and Z. Švestka), North-Holland Publ. Co., Amsterdam, p. 81.

    Google Scholar 

  • Hallam, K. L.: 1964, in W. N. Hess (ed.) AAS-NASA Symp. on the Physics of Solar Flares, NASA SP-50, U.S. Government Printing Office, Washington, D.C., p. 63.

    Google Scholar 

  • Harvey, K. L.: 1971, Solar Phys. 16, 423.

    Google Scholar 

  • Hinteregger, H. E. and Hall, L. A.: 1969, Solar Phys., 6, 175.

    Google Scholar 

  • Janssens, T. J. and White, K. P., III: 1970, Solar Phys. 11, 299.

    Google Scholar 

  • Kane, S. R. and Donnelly, R. F.: 1971, Astrophys. J. 164, 151.

    Google Scholar 

  • Kane, S. R. and Winckler, J. R.: 1969, Solar Phys. 6, 304.

    Google Scholar 

  • McClinton, A. T. Jr.: 1968, NRL Space Research Seminar (U.S. Naval Research Lab., Washington, D.C.), 63.

    Google Scholar 

  • McIntosh, P. S. and Donnelly, R. F.: 1971, submitted to Solar Phys.

  • Moreton, G. E.: 1964, in W. N. Hess (ed.), AAS-NASA Symp. on the Physics of Solar Flares, NASA SP-50, U.S. Government Printing Office, Washington, D.C., p. 209.

    Google Scholar 

  • Najita, K. and Orrall, F. Q.: 1970, Solar Phys. 15, 176.

    Google Scholar 

  • Neupert, W. M., White, W. A., Gates, W. J., Swartz, M., and Young, R. M.: 1969, Solar Phys. 6, 183.

    Google Scholar 

  • Noyes, R. W., Withbroe, G. L., and Kirshner, R. P.: 1970, Solar Phys. 11, 388.

    Google Scholar 

  • Parks, G. K. and Winckler, J. R.: 1969a, Astrophys. J. 155, L117.

    Google Scholar 

  • Parks, G. K. and Winckler, J. R.: 1969b, Trans. Am. Geophys. Union 50, paper STS13, 299.

    Google Scholar 

  • Reeves, E. M., Dupree, A. K., Goldberg, L., Huber, M., Noyes, R. W., Parkinson, W. H., and With-broe, G. L.: 1970, paper S4-2, presented at The International Symposium on Solar-Terrestrial Physics, Leningrad, U.S.S.R.

  • Richards, D. W.: 1970, preliminary report, Air Force Cambridge Research Laboratories, Bedford, Mass.

  • Švestka, Z.: 1970, Solar Phys. 13, 471

    Google Scholar 

  • Strauss, F. M., Papagiannis, M. D., and Aarons, J.: 1969, J. Atmospheric Terrest. Phys. 31, 1241.

    Google Scholar 

  • Thomas, R. J.: 1970, ‘Solar Soft X-Radiation’, Ph. D. Thesis and final rept. of ORA Project 05567, Dept. of Astronomy, U. of Michigan, Ann Arbor.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. NOAA, Environmental Research Laboratories Boulder, Colo., U.S.A.

    Richard F. Donnelly

Authors
  1. Richard F. Donnelly
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Donnelly, R.F. Extreme ultraviolet flashes of solar flares observed via sudden frequency deviations: Experimental results. Sol Phys 20, 188–203 (1971). https://doi.org/10.1007/BF00146110

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00146110

Keywords

Search

Navigation